diff options
| author | Ram Pai <linuxram@us.ibm.com> | 2005-11-07 17:19:33 -0500 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-07 18:18:10 -0800 |
| commit | 03e06e68ff76294e53ffa898cb844d2a997b043e (patch) | |
| tree | df17444b2c9b89e1eed75e09d46ea36c40ebd1df | |
| parent | 07b20889e3052c7e77d6a6a54e7e83446eb1ba84 (diff) | |
| download | lwn-03e06e68ff76294e53ffa898cb844d2a997b043e.tar.gz lwn-03e06e68ff76294e53ffa898cb844d2a997b043e.zip | |
[PATCH] introduce shared mounts
This creates shared mounts. A shared mount when bind-mounted to some
mountpoint, propagates mount/umount events to each other. All the
shared mounts that propagate events to each other belong to the same
peer-group.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | fs/namespace.c | 3 | ||||
| -rw-r--r-- | fs/pnode.c | 13 | ||||
| -rw-r--r-- | fs/pnode.h | 4 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 | ||||
| -rw-r--r-- | include/linux/mount.h | 2 |
5 files changed, 21 insertions, 2 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 3782923d6d4d..f6861a5487df 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -68,6 +68,7 @@ struct vfsmount *alloc_vfsmnt(const char *name) INIT_LIST_HEAD(&mnt->mnt_mounts); INIT_LIST_HEAD(&mnt->mnt_list); INIT_LIST_HEAD(&mnt->mnt_expire); + INIT_LIST_HEAD(&mnt->mnt_share); if (name) { int size = strlen(name) + 1; char *newname = kmalloc(size, GFP_KERNEL); @@ -1113,7 +1114,7 @@ long do_mount(char *dev_name, char *dir_name, char *type_page, data_page); else if (flags & MS_BIND) retval = do_loopback(&nd, dev_name, flags & MS_REC); - else if (flags & MS_PRIVATE) + else if (flags & (MS_SHARED | MS_PRIVATE)) retval = do_change_type(&nd, flags); else if (flags & MS_MOVE) retval = do_move_mount(&nd, dev_name); diff --git a/fs/pnode.c b/fs/pnode.c index aaa0dffda12a..1e22165ea41f 100644 --- a/fs/pnode.c +++ b/fs/pnode.c @@ -11,7 +11,18 @@ #include <linux/fs.h> #include "pnode.h" +/* return the next shared peer mount of @p */ +static inline struct vfsmount *next_peer(struct vfsmount *p) +{ + return list_entry(p->mnt_share.next, struct vfsmount, mnt_share); +} + void change_mnt_propagation(struct vfsmount *mnt, int type) { - mnt->mnt_flags &= ~MNT_PNODE_MASK; + if (type == MS_SHARED) { + mnt->mnt_flags |= MNT_SHARED; + } else { + list_del_init(&mnt->mnt_share); + mnt->mnt_flags &= ~MNT_PNODE_MASK; + } } diff --git a/fs/pnode.h b/fs/pnode.h index 33549a3a74eb..ab1bdaee4e08 100644 --- a/fs/pnode.h +++ b/fs/pnode.h @@ -10,5 +10,9 @@ #include <linux/list.h> #include <linux/mount.h> + +#define IS_MNT_SHARED(mnt) (mnt->mnt_flags & MNT_SHARED) +#define CLEAR_MNT_SHARED(mnt) (mnt->mnt_flags &= ~MNT_SHARED) + void change_mnt_propagation(struct vfsmount *, int); #endif /* _LINUX_PNODE_H */ diff --git a/include/linux/fs.h b/include/linux/fs.h index 6c431086abb3..551fba303cf8 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -105,6 +105,7 @@ extern int dir_notify_enable; #define MS_REC 16384 #define MS_VERBOSE 32768 #define MS_PRIVATE (1<<18) /* change to private */ +#define MS_SHARED (1<<20) /* change to shared */ #define MS_POSIXACL (1<<16) /* VFS does not apply the umask */ #define MS_ACTIVE (1<<30) #define MS_NOUSER (1<<31) diff --git a/include/linux/mount.h b/include/linux/mount.h index 8eadd3b65899..2582559718fc 100644 --- a/include/linux/mount.h +++ b/include/linux/mount.h @@ -20,6 +20,7 @@ #define MNT_NOSUID 0x01 #define MNT_NODEV 0x02 #define MNT_NOEXEC 0x04 +#define MNT_SHARED 0x10 /* if the vfsmount is a shared mount */ #define MNT_PNODE_MASK 0x30 /* propogation flag mask */ struct vfsmount { @@ -36,6 +37,7 @@ struct vfsmount { char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ struct list_head mnt_list; struct list_head mnt_expire; /* link in fs-specific expiry list */ + struct list_head mnt_share; /* circular list of shared mounts */ struct namespace *mnt_namespace; /* containing namespace */ int mnt_pinned; }; |